It is customary for pizzas to be prepared for take-out by customers, or for delivery to the houses of persons who place orders for pizzas by telephone. One format for packaging pizzas in such circumstances is to place the pizza in a single-walled, paper-board box that folds up from a flat paper-board blank. Such boxes customarily enclose the pizza with a lid.
Boxes of this type provide only a moderate degree of heat retention for the pizza during delivery. If the boxes are unvented, an extended delivery period can result in a pizza which is both cool and soggy.
To maintain the warmth of freshly prepared pizzas, delivery is sometimes effected by placing the boxed pizza within an insulated vinyl outer bag. While this delivery system maintains pizza warmth for a longer period of time, the vapour-proof character of the combined containers increases the likelihood that the pizza will arrive at its destination in a soggy condition.
The use of paper-board boxes of adequate strength to contain pizzas is relatively expensive. Efforts have been made to develop less expensive means for packaging pizzas for delivery to customers.
A cheaper container which allows moisture to evaporate has been proposed in the form of a paperboard tray with at least a partially open top. To retain heat and protect the pizza from being soiled, such a tray may be placed within a paper bag. Patents proposing such a system include U.S. Pat. No. 4,301,960 to Alexander et al and U.S. Pat. No. 4,913,340 to Hitch. In this second reference, the tray is described as having an open central portion on the top and upright interlocking sides that are held in place by interlocking tabs. The erect side walls protect the pizza from contact with the enveloping bag.
A further reference which provides, as a container for pizzas, a paperboard tray with side walls and no lid that is intended to slide within a paper bag is U.S. Pat. No. 4,494,689 to Ilitch. Again in this reference the side walls of the container are inter-engaged at their corners to hold the walls in an upright position and protect the upper surface of the pizza from contact with the bag.
In practice, it is also known to provide a lower cost tray wherein only two opposing side walls are provided. In this case, the enveloping bag is sized to hold the unsupported walls in a partially elevated position. The side walls, which are bent-up from the bottom panel of the tray along score lines, possess a natural resilience that causes them to spring outwardly. With a properly sized bag, this springing action tightens the bag and reduces any tendency for the bag overlying the pizza to be slack and contact the pizza's upper surface.
The foregoing references reflect minimal cost formats for the packaging of pizza. While the use of the paper bag for enclosure of the pizza allows for moisture to escape (through permeation of the paper), the thermal insulating qualities of this packaging format are low.
A more expensive packaging format that aspires to provide increased thermal insulation for pizza is shown in U.S. Pat. No. 4,919,326 to Deiger. This reference describes the use of double-walled corrugated paperboard to provide a container. To prevent moisture from accumulating within the closed box of this invention ventilation openings are provided.
Dieger recognizes that pizzas are capable of releasing oil or grease from their hot, lower crust. "Chipboard" containers are specifically identified as suffering under such circumstances. To protect the corrugated bottom of his container Deiger proposes lining at least the bottom of the box with a layer of impermeable insulative sheeting, such as polystyrene.
While the use of a polystyrene lining protects the cardboard of the box from oil and moisture, Deiger recognizes that its non-permeable character will tend to make the underside of the pizza crust soggy. To meet this problem, he proposes that a lattice of air channels be pressed into the polystyrene covering.
While the Deiger box may perform in a superior manner, it will only do so at a considerable cost. Corrugated doublesided paperboard is substantially more expensive than single sheets of paperboard. It is accordingly highly undesirable to use such a format box for the one-use function of a single pizza delivery.
A hybrid packaging format is proposed in U.S. Pat. No. 4,922,626 to Fiddler. In this reference, a standard pizza box with vent openings to permit moisture to escape is carried within a larger, insulative container which also contains a motorized fan, heater and desiccant material. Demoisturizing air is then circulated over the pizza in cyclic manner, within the outer container. Power for the motor and heater is provided through the cigarette lighter of an automobile.
Such an arrangement is intended to replace the more common insulated vinyl bag within which simply boxed pizzas are now delivered. It is, however, a very expensive means of packaging pizza for delivery. This will be particularly appreciated where a delivery vehicle is required on occasion to carry two or four pizzas to different locations. Fiddler would then require a capital investment in a corresponding number of high cost outer containers.
From the foregoing it is apparent that a pizza packaging system is required that is low in cost yet ensures that pizzas, after the time delay required for delivery, are still warm, without having become substantially soggy. The present invention addresses this problem. Through its combination of components, this invention will meet both the customer's desire to receive delivered pizzas which are still highly palatable, in terms of warmth and crispness, and the pizza supplier's desire to minimize packaging costs.
The invention will first be summarized. Then a preferred embodiment will be described in detail, with reference to the drawings. The disclosure will then end with claims that further describe and define the invention in its most general and more specific aspects.